Unsaturated phosphorochloridates

The conj ugate addition of lithium dimethylcuprate and other organoeopper reagents to a,/ -unsaturated ketones is a reaction which has had wide application and which has been fairly well studied.6 In order that the positional specificity which has been conferred upon the enolate anions generated by such additions might be maintained, these intermediates have been intercepted with acetic anhydride,6 chlorotrimethylsilane, and diethyl phosphorochloridate.4 8... 

Ammonium perchlorate, Impurities, 3998 Azidoacetic acid, 0770 f Aziridine, Acids, 0859 Benzoyl azide, 2694 Benzyl chloroformate, 2926 1,2-Bis(difluoroamino)-/V-nitroethylamine, 0799 Bromine trioxide, 0259 2-Butanone oxime, 1649 2-Butyne-l,4-diol, 1523 Butyraldehyde oxime, 1650 Carbon, Unsaturated oils, 0297 Chlorine, Carbon disulfide, 4041 f l-Chloro-2,3-epoxypropane, Contaminants, 1158 Cyanogen chloride, 0322 Diethyl phosphorochloridate, 1675 f 1,1-Difluoroethylene, 0696... 

Harvey, R.G., Reactions of triethyl phosphite with activated olefins. Tetrahedron, 22, 2561, 1966. Okamoto, Y, A convenient preparation of dialkyl 3-(dialkoxyphosphinyl)-l-propenyl phosphate derivatives. Addition of the mixed reagent trialkyl phosphite/diaUcyl phosphorochloridate to a,P-unsaturated aldehyde, Chem. Lett., 87, 1984. 

Olefin synthesis from a,p-unsaturated ketones. Ireland and Pflster1 have extended the procedure of Kenner and Williams (1,248, ref. 2) for deoxygenation of phenols to conversion of a,/3-unsaturated ketones into olefins. For example, the a,)3-unsaturated ketone (1) was reduced by lithium-ammonia to give an enolate anion which reacted with diethyl phosphorochloridate to give the phosphate ester (2) in 56% yield. This ester was reduced in high yield by lithium in a mixture of ethylamine and r-butanol to the olefin (3). It is noteworthy that only one olefin is formed. Actually the conversion of (1) into (3) can be carried out in 50% yield without isolation of the diethyl enol phosphate. 

The sequence can also be applied to the enolate anion formed by conjugate addition of organometallic reagents to a,/8-unsaturated ketones. Thus addition of diethyl phosphorochloridate to a mixture of A4-cholestene-3-one (4) and dimethyl-copperlithium gives the diethyl enol phosphate (5) in 55% yield. Reduction of the ester gives the olefin (6) in high yield. 

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